Chi Man Leung

Epidemiology of Inflammatory Bowel Disease from 1981 to 2014: Results from a Territory-Wide Population-Based Registry in Hong Kong

Background:Incidence of inflammatory bowel disease (IBD) is increasing in Asia, but population-based prevalence data are limited. This study examined IBD incidence and prevalence based on results of a territory-wide IBD registry in Hong Kong. Methods:We collected data on 2575 patients with IBD (1541 ulcerative colitis [UC], 983 Crohns disease [CD], 51 IBD unclassified) from 1981 to 2014 using hospital and territory-wide administrative coding system. Prevalence and incidence, disease phenotype, surgery, and mortality were analyzed. Results:Adjusted prevalence of IBD, UC, CD, and IBD unclassified per 100,000 individuals in 2014 were 44.0, 24.5, 18.6, and 0.9, respectively. Age-adjusted incidence of IBD per 100,000 individuals increased from 0.10 (95% confidence interval, 0.06–0.16) in 1985 to 3.12 (95% confidence interval, 2.88–3.38) in 2014. UC:CD incidence ratio reduced from 8.9 to 1.0 over 30 years (P < 0.001). A family history of IBD was reported in 3.0% of patients. Stricturing or penetrating disease was found in 41% and perianal disease in 25% of patients with CD. 5-aminosalicylate use was common in UC (96%) and CD (89%). Cumulative rates of surgery for CD were 20.3% at 1 year and 25.7% at 5 years, and the corresponding rates for UC were 1.8% and 2.1%, respectively. Mortality for CD and UC was not significantly different from the general population. Conclusions:In a population-based study in Hong Kong, prevalence of IBD is lower than in the west although comparable to that of other East Asian countries. Complicated CD is common. Overall mortality remains low in Asians with IBD.

Natural History of Elderly-onset Ulcerative Colitis: Results from a Territory-wide Inflammatory Bowel Disease Registry

BACKGROUND AND AIMS Data on the natural history of elderly-onset ulcerative colitis [UC] are limited. We aimed to investigate clinical features and outcomes of patients with elderly-onset UC. METHODS Patients with a confirmed diagnosis of UC between 1981 and 2013, from 13 hospitals within a territory-wide Hong Kong Inflammatory Bowel Disease Registry, were included. Clinical features and outcomes of elderly-onset patients, defined as age ≥ 60 years at diagnosis, were compared with those of non-elderly-onset disease [< 60 years at diagnosis]. RESULTS We identified 1225 patients, of whom 12.8% [157/1225; 56.1% male] had elderly-onset UC. Median duration of follow-up was 11 years [interquartile range, 6-16 years]. Age-specific incidence of elderly-onset UC increased from 0.1 per 100000 persons before 1991 to 1.3 per 100000 persons after 2010. There were more ex-smokers [32.2% vs. 12.2%, p < 0.001] and higher proportion of comorbidities [p < 0.001] in elderly-onset than non-elderly-onset patients. Disease extent, corticosteroids, immunosuppressants use, and colectomy rates were similar between the two groups. Elderly-onset disease was an independent risk factor for cytomegalovirus infection [odds ratio 2.9, 95% confidence interval 1.6-5.2, p < 0.001]. More elderly-onset patients had Clostridium difficile infection [11.0% vs. 5.4%, p = 0.007], hospitalisation for UC exacerbation [50.6% vs. 41.8%, p = 0.037], colorectal cancer [3.2% vs. 0.9%, p = 0.033], all-cause mortality [7.0% vs. 1.0%, p < 0.001], and UC-related mortality [1.9% vs. 0.2%, p = 0.017] than non-elderly-onset patients. CONCLUSIONS Elderly-onset UC patients are increasing in number. These patients have higher risk of opportunistic infections, hospitalisation, colorectal cancer, and mortality than non-elderly-onset patients. Management and therapeutic strategies in this special group need careful attention.

Low-dose azathioprine is effective in maintaining remission in steroid-dependent ulcerative colitis: results from a territory-wide Chinese population-based IBD registry

Background: Whether low-dose azathioprine (AZA) is effective in maintaining remission in patients with steroid-dependent ulcerative colitis (UC) remains unclear. We assessed the efficacy and safety of low-dose AZA in a Chinese population with UC. Methods: We identified steroid-dependent UC patients in clinical remission on AZA maintenance therapy from a territory-wide IBD Registry. Standard- and low-dose AZA were defined as at least 2 mg/kg/day and less than 2 mg/kg/day, respectively. Relapse rates were analyzed by Kaplan–Meier analysis and compared using log-rank test. Results: Among 1226 UC patients, 128 (53% male, median duration on AZA 44 months) were included. Median maintenance AZA dose was 1.3 mg/kg/day. 97.7% of the patients were on concomitant oral 5-aminosalicylic acid. Cumulative relapse-free rates in patients on standard-dose and low-dose AZA were 71.2%, 52.8% and 45.2%, and 71.8%, 55.3% and 46.2% at 12, 24 and 36 months, respectively (p = 0.871). Relapse rate within 12 months was higher in patients who withdrew compared with those who maintained on AZA (52.6% versus 29.4%; p = 0.045). Mean corpuscular volume increased after AZA therapy in both of the low-dose [median (interquartile range, IQR): 88.2 (81.4–92.2) versus 95.1 (90.1–100.9) fl, p < 0.001] and standard-dose subgroups [median (IQR) 86.8 (76.9–89.9) versus 94.7 (85.9–99.7) fl, p < 0.001]. Leukopenia occurred in 21.1% of the patients. Patients on standard dose had a higher risk for leukopenia than those on low-dose AZA [odds ratio (OR) 3.9, 95% CI 1.9–8.2, p < 0.001]. Conclusions: In the Chinese population, low-dose AZA is effective for maintaining remission in steroid-dependent UC patients. Standard-dose AZA was associated with more than threefold increased risk of leukopenia.

Cancer Risk in 2621 Chinese Patients with Inflammatory Bowel Disease: A Population-based Cohort Study

Background: Studies on cancer risk in inflammatory bowel disease (IBD) have yielded inconsistent results. We conducted a population-based study to determine the risk of cancer in patients with Crohns disease (CD) and ulcerative colitis (UC). Methods: Using a territory-wide IBD registry in Hong Kong, we identified 2621 patients with IBD and no history of cancer from 1990 to 2016. We followed them from diagnosis until either September 2016, cancer development, proctocolectomy, or death. Standardized incidence ratios (SIRs) of overall cancer and site-specific cancers were calculated. Results: Of 2621 patients with IBD (1108 CD; 1603 UC; median age, 49 yr; 59.5% men) followed for 26,234 person-years, 88 patients developed cancer after IBD diagnosis. Patients with CD had an increased risk of anorectal cancers (SIR 4.11; 95% confidence interval (CI), 1.84–9.14) and hematological cancers (SIR 3.86, 95% CI, 1.61–9.27) including leukemia (SIR 5.98; 95% CI, 1.93–18.54). Nonmelanoma skin cancer was significantly increased in both CD and UC (CD: SIR 13.88; 95% CI, 1.95–98.51; UC: SIR 9.05; 95% CI, 2.26–36.19). Patients with CD had a higher risk of renal-cell carcinoma (SIR 6.89; 95% CI, 2.22–21.37), and patients with UC had a higher risk of prostate cancer (SIR 2.47; 95% CI, 1.24–4.95). Conclusions: In a population-based study, Chinese patients with CD are at an increased risk of anorectal cancers and hematological cancers compared with the general population. A higher risk of nonmelanoma skin cancer was also observed in CD and UC. Cancer surveillance should be considered.

Significant Medical and Surgical Morbidity in Perianal Crohn’s Disease: Results from a Territory-Wide Study

Background The presence of perianal fistulas in Crohns disease [CD] denotes increased disease aggressiveness. We studied the epidemiology and clinical outcomes of perianal CD [PCD] using the Hong Kong territory-wide IBD Registry [HKIBDR]. Methods Consecutive patients with PCD were identified from the HKIBDR, and disease characteristics, treatments, and outcomes were analysed. The risks for medical and surgical therapies were assessed using Kaplan-Meier analysis. Results Among 981 patients with CD with 10530 patient-years of follow-up, 283 [28.8%] had perianal involvement, of which 120 [42.4%] were as first presentation. The mean age at diagnosis of PCD was 29.1 years, and 78.8% were male. The median follow-up duration was 106 months (interquartile range [IQR]: 65-161 months]. Perianal fistula [84.8%] and perianal abscess [52.7%] were the two commonest forms. Male, younger age at diagnosis of CD, and penetrating phenotypes were associated with development of PCD in multivariate analysis. Of 242 patients with fistulizing PCD, 70 [29.2%] required ≥5 courses of antibiotics, and 98 [40.5%] had ≥2 surgical procedures. Nine patients required defunctioning surgery and 4 required proctectomy. Eighty-four patients [34.7%] received biologics. Cumulative probabilities for use of biologics were 4.7%, 5.8%, and 8.6% at 12 months, 36 months, and 96 months, respectively, while the probabilities for surgery were 67.2%, 71.6%, and 77.7%, respectively. Five mortalities were recorded, including 2 cases of anal cancer, 2 CD-related complications, and one case of pneumonia. Conclusion Over 40% of CD patients presented with perianal disease at diagnosis. Patients with PCD had poor outcome, with young age of onset, multiple antibiotic use, and repeated surgery.

Su1303 Prevalence and Disease Characteristics of Inflammatory Bowel Disease (IBD) in Chinese: Results From a Nationwide Population-Based Registry

Prevalence and Disease Characteristics of Inflammatory Bowel Disease (IBD) in Chinese: Results From a Nationwide Population-Based Registry Siew C Ng, Wai K. Leung, Michael K. Li, Chi Man Leung, Yee Tak HUI, Carmen Ka Man Ng, Fu Hang Lo, Steve Tsang, Ching Kong Loo, Yiu Kay Chan, Kam Hon Chan, Aric J. Hui, Wai Hung Chow, Jessica Ching, Tiffany ML Chung, Catherine YY Iu, Marcus Harbord, Ivan Fan Ngai Hung, Wai Cheung Lao, Shun Fung Sze, Marc Tin Long Wong, Rita Leung, Vivian W. Tsang, Belsy Chung Yan Lam, Raymond Wai Hung Tong, Edwin Hok Shing Shan, Lai Yee Mak, Sai Ho Wong, Justin C. Wu, Francis K. L. Chan, Joseph J. Y. Sung